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Wed, 13 May 2020 13:33:17 +0000 (GMT) From: Marek Szyprowski To: dri-devel@lists.freedesktop.org, iommu@lists.linux-foundation.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Cc: Marek Szyprowski , Christoph Hellwig , Robin Murphy , Bartlomiej Zolnierkiewicz , linux-arm-kernel@lists.infradead.org, David Airlie , Daniel Vetter , Mauro Carvalho Chehab , Laurent Pinchart , Kieran Bingham , linux-renesas-soc@vger.kernel.org, linux-media@vger.kernel.org Subject: [PATCH v5 29/38] drm: rcar-du: fix common struct sg_table related issues Date: Wed, 13 May 2020 15:32:36 +0200 Message-Id: <20200513133245.6408-29-m.szyprowski@samsung.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200513133245.6408-1-m.szyprowski@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA0WSe0hTYRjG+85tx7XFaV38stJY9ygvzOCgXSnihHQBISLKXHnUSqduWimE o5jUvKAWWCpiGmXeplOnuMq0UtNakdeh5mXqTCnNy8qY1tYx++/3PO/z8rx8fCQqasKdyEuy SFYuk4aICT6mq5817HL+ofdz/212pBMNbxG69L4Gp3/rUlC6dWacoJ8WvEHo7BpverI9HtB3 Uh7x6OnWfoTWmtpxuqU6k6ATSipwuuLLN4Quet3Dox9rrQhdOzGIH6CYwqxCwDy3ZGNMxu0H OKPNv0MwlZY+nOmNb0CYskexTNe8CWXudj4BjN6oJJik8nzATGmdTwrO8PcEsCGXrrJyt33+ /OCM2UEkfHzN9bniZEwJjKvUwIGElCc056pwNeCTIioPwLaaAoIT0wB+zzXyODEF4JB5Dvm3 8nnQjHKDJwBWJtWDxZVm/WtgTxGUB1R/VRN2XkmpAGxMFNgZpawoTMvcb+cVlC9U9yTidsao zXBgpNyWJ0khtRcOP/PgylxgQclL1M4ONnu0uwazd0FqgAcnzd0LFx2GI7kfFngFHG0o53G8 DjbfTVhYuAVgv6GIx4kEAFtu3gdcyht2G379bUap7VBT7cbZB+F77QRmtyG1DHZ+Xc7dvwym 6tJQzhbC23EiLr0FpjcUL9bWfvyEcszA0YlUjHufVwCWDXTxkoFL+v+ybADygSMbpQgNYhUS GXvNVSENVUTJglwvhoVqge2HNc83zFSBF9YLdYAigVgg7OvQ+4lw6VVFdGgdgCQqXik8rrFZ wgBpdAwrDzsvjwphFXVgLYmJHYWSnC/nRFSQNJK9wrLhrPzfFCEdnJTg6LbCZI38nXaJ0aLy Uvm36XbfO0+srjFa0w96KQ+Mx5kOmy77VB3aOTuZOcQ//thnQ2xcWlpS38MbJaePCF0kljWe Tc8DT+XUW9wjIqeO9cmm9V6CE2M/ayURPXm7Z3rXb1zSmZFnHb5ytidm6VhHqSzQ7Nu6Se9/ sjF961xxVsBFMaYIlnrsQOUK6R8rqz3eXQMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrDIsWRmVeSWpSXmKPExsVy+t/xu7qy33fHGdxsMbPoPXeSyWLjjPWs Fv+3TWS2uPL1PZvFytVHmSwW7Le2+HStm9Gic+ISdosvVx4yWWx6fI3V4vKuOWwWPRu2slps ffmOyWLtkbvsFss2/WGyOPjhCauDgMeaeWsYPfZ+W8DiMbtjJqvHplWdbB7bvz1g9bjffZzJ Y/OSeo/b/x4ze0y+sZzRY/fNBjaPvi2rGD0+b5IL4InSsynKLy1JVcjILy6xVYo2tDDSM7S0 0DMysdQzNDaPtTIyVdK3s0lJzcksSy3St0vQy5j98wlTwXvJir/rJrA0MN4U7WLk5JAQMJG4 9+Q5cxcjF4eQwFJGiV2fpjBDJGQkTk5rYIWwhSX+XOtigyj6xChxs3kNG0iCTcBQoustREJE oJNRYlr3R3YQh1mghUXiw6eHLCBVwgKBEtt/TAQbyyKgKvHoxRagDg4OXgFbiWd7DCE2yEus 3nAArIQTKPzqzn6wViGBfIm9i/exTWDkW8DIsIpRJLW0ODc9t9hIrzgxt7g0L10vOT93EyMw prYd+7llB2PXu+BDjAIcjEo8vBa3dscJsSaWFVfmHmKU4GBWEuH1Ww8U4k1JrKxKLcqPLyrN SS0+xGgKdNNEZinR5HxgvOeVxBuaGppbWBqaG5sbm1koifN2CByMERJITyxJzU5NLUgtgulj 4uCUamAsfB+pVv3A2GGfnsrm3kPb/7w4tr3gS3lyfZool0LcbMuLHEcSJu57HL68PXvxWxe7 5xeeBLi/OrBrD8dKjmnLJ3s8aLhy9WDTiknTU0+ziu0Je/3q44/Gg0sDuuoOqDTZ1d7ybO3Z +l2rqd/70ppT964HalTpzGNpuu/V+fJTzLUVh6/Gb/v4W4mlOCPRUIu5qDgRAHMWcbK/AgAA X-CMS-MailID: 20200513133317eucas1p27aead4025db2da13e5b7c3e14a7cd79d X-Msg-Generator: CA X-RootMTR: 20200513133317eucas1p27aead4025db2da13e5b7c3e14a7cd79d X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200513133317eucas1p27aead4025db2da13e5b7c3e14a7cd79d References: <20200513132114.6046-1-m.szyprowski@samsung.com> <20200513133245.6408-1-m.szyprowski@samsung.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The Documentation/DMA-API-HOWTO.txt states that the dma_map_sg() function returns the number of the created entries in the DMA address space. However the subsequent calls to the dma_sync_sg_for_{device,cpu}() and dma_unmap_sg must be called with the original number of the entries passed to the dma_map_sg(). struct sg_table is a common structure used for describing a non-contiguous memory buffer, used commonly in the DRM and graphics subsystems. It consists of a scatterlist with memory pages and DMA addresses (sgl entry), as well as the number of scatterlist entries: CPU pages (orig_nents entry) and DMA mapped pages (nents entry). It turned out that it was a common mistake to misuse nents and orig_nents entries, calling DMA-mapping functions with a wrong number of entries or ignoring the number of mapped entries returned by the dma_map_sg() function. To avoid such issues, lets use a common dma-mapping wrappers operating directly on the struct sg_table objects and use scatterlist page iterators where possible. This, almost always, hides references to the nents and orig_nents entries, making the code robust, easier to follow and copy/paste safe. dma_map_sgtable() function returns zero or an error code, so adjust the return value check for the vsp1_du_map_sg() function. Signed-off-by: Marek Szyprowski Reviewed-by: Laurent Pinchart --- For more information, see '[PATCH v5 00/38] DRM: fix struct sg_table nents vs. orig_nents misuse' thread: https://lore.kernel.org/linux-iommu/20200513132114.6046-1-m.szyprowski@samsung.com/T/ --- drivers/gpu/drm/rcar-du/rcar_du_vsp.c | 3 +-- drivers/media/platform/vsp1/vsp1_drm.c | 8 ++++---- 2 files changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c index 5e4faf2..2fc1816 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_vsp.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_vsp.c @@ -197,9 +197,8 @@ int rcar_du_vsp_map_fb(struct rcar_du_vsp *vsp, struct drm_framebuffer *fb, goto fail; ret = vsp1_du_map_sg(vsp->vsp, sgt); - if (!ret) { + if (ret) { sg_free_table(sgt); - ret = -ENOMEM; goto fail; } } diff --git a/drivers/media/platform/vsp1/vsp1_drm.c b/drivers/media/platform/vsp1/vsp1_drm.c index a4a45d6..86d5e3f 100644 --- a/drivers/media/platform/vsp1/vsp1_drm.c +++ b/drivers/media/platform/vsp1/vsp1_drm.c @@ -912,8 +912,8 @@ int vsp1_du_map_sg(struct device *dev, struct sg_table *sgt) * skip cache sync. This will need to be revisited when support for * non-coherent buffers will be added to the DU driver. */ - return dma_map_sg_attrs(vsp1->bus_master, sgt->sgl, sgt->nents, - DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); + return dma_map_sgtable(vsp1->bus_master, sgt, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); } EXPORT_SYMBOL_GPL(vsp1_du_map_sg); @@ -921,8 +921,8 @@ void vsp1_du_unmap_sg(struct device *dev, struct sg_table *sgt) { struct vsp1_device *vsp1 = dev_get_drvdata(dev); - dma_unmap_sg_attrs(vsp1->bus_master, sgt->sgl, sgt->nents, - DMA_TO_DEVICE, DMA_ATTR_SKIP_CPU_SYNC); + dma_unmap_sgtable(vsp1->bus_master, sgt, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); } EXPORT_SYMBOL_GPL(vsp1_du_unmap_sg);